Fibrous structures



March 22, 1966 Filed Dec. 13. 1961 Fig.1

5 Sheets-Sheet 1 lNVENTOR ART/ UR C. WROTNO WSK/ BY Fm v 222 ATTO R N Y5March 22, 1966 A. c. WROTNOWSKI 3,241,673 I FIBROUS STRUCTURES FiledDec. 15, 1961 3 Sheets-Sheet z INVENTOR ARTHUR C. WROTNOWSKI BY 7? a,ORNZYS ATT March 22, 1966 A. c. WROTNOWSKI 3,241,678

FIBROUS STRUCTURES Filed Dec. 13. 1961 5 Sheets-Sheet 3 INVENTOR. ARTHURC. WROT/VOWSK/ Wm M W ATTO AE'YS United States Patent 3,241,678 FIBROUSSTRUCTURES Arthur C. Wrotnowski, Greenwich, Conn., assignor to AmericanFelt Company, Glenville, Conm, a corporation of Massachusetts Filed Dec.13, 1961, Ser. No. 159,023 3 Claims. (Cl. 210231) This is acontinuation-in-part of application Serial No. 724,973, filed March 31,1958, now abandoned, in the name of Arthur C. Wrotnowski.

This invention relates to filter elements of the nonwoven non-metallictype, and particularly to a unitary fibrous filter plate for use in aplate and frame type filter.

Plate and frame type filters are Well known in the art, an examplethereof being shown in US. Patent No. 891,393. Such arrangementsnormally have frames which are recessed, said frames having transversepassages extending from one face to the other. The transverse passagesprovide a fluid path along the filter in cooperation with similartransverse passages in adjoining plates and frames extending the lengthof the filter. The frames also have passages extending from said recessthereof to the transverse inlet passage thereof. In prior practice, theplate means have been composed of a plurality of elements, said platemeans being located in the press between pairs of the aforementionedframes. Each of the prior plate arrangements has been composed of aheavy separating member having a waffle or frustum design dressed withwoven filter cloth on either side thereof. The woven cloth has beencarried in various manners on the face of the plate. In many instances,the separating plate has been of cast iron or heavy material. The platearrangements have been thick with resultant undesirable filter lengthand have been awkward to handle and replace. Furthermore, because theseparating plate is impervious, any difference of pressure between thesides thereof due, for example, to the filter cloth on one side beingclogged, may cause breakage of the plate.

One of the objects of the present invention is to provide a fibrousfilter plate element which is unitary, easy to handle and is economicalto make and use.

Another of the objects of the invention is to provide a unitary filterplate combination having improved filtering characteristics.

Another of the objects of the invention is to provide a non-metallicplate assembly.

In one aspect of the invention, a plate assembly may comprise aninternal drainage member having drainage channels therein and having anoutlet zone means, the internal drainage member preferably being made ofa suitable felt such as a synthetic fiber felt. Filter plate felt fabricor media members can be cut'to the desired shape and placed on eitherside of the drainage member. Preferably, but not necessarily, aseparating or spacer means is used between said two outside filter mediaface members, said separating means having a cutout portion or recessincluding an outlet zone to receive the internal drainage member and itsdrainage zone or appended area. The complete assembly can be joinedaround its edge zone by pressing and sealing, such as by fusing or by asuitable adhesive, a restricted peripheral zone thereof, which zone alsowill provide gasketing surfaces on either side of the laminated plateagainst which adjoining frame members can be held in abutting andsealing relationship. The joining can be by fusing or by using asuitable adhesive. In one form, the side plates and gasketing area aresubstantially flat or in a single plane. The drainage member preferablymay be of mechanically interlocked felt which is formed by subjectingthe fiber batt to a needling operation. The plates and frames havepassages extending therethrough or across their faces which registerwhen in assembled relation to form outlet and inlet passages for thefluid.

In another aspect of the invention, a plate filter assembly may includea central impervious plate element having a plurality of transversethrough passages adjacent the corners thereof. Frame members may belocated on each side of the central plate and may surround drainageelements in the form of grid, lattice or perforated members, and one ofthe through passages of the central plate may communicate with thespaces within said frame members that are occupied by the grid orlattice members. Each frame member may be covered with a sheet of filtermedia, retaining the grid members in place, and the entire assembly maybe sealed together forming a unitary assembly.

These and other objects, advantages and features of the invention willbecome apparent from the following description and drawings which aremerely exemplary.

In the drawings:

FIG. 1 is a broken view of one form of frame and filter press with whichthe present invention can be used.

FIG. 2 is an exploded view showing the various ele ments before assemblyof a plate for use in FIG. 1.

FIG. 3 illustrates the plate of FIG. 2 in an assembled relationship.

FIG. 4 is a sectional view looking in the direction of line 4-4 of FIG.3.

FIG. 5 is a view of a plate with an open discharge.

FIG. 6 is an exploded perspective view of a modified form of filterplate.

The frame and filter press arrangement can have rigid end members 10, 11(FIG. 1), said end members being held in assembled relation in anysuitable manner, such as by rod or strut means 12 on either side of theplates and frames. Frame members 13 are located between plate members14, said frame members having hollow or recessed interior portions 15with passageways 16 connecting the interior 15 with transverse inletpassages 17, said transverse passages extending laterally across theframe between opposite faces of the frame. The joined inlet passages inthe various elements register and are connected with supply or inletpipe 18. Similar outlet passages not connected to the recess 15 are alsoprovided in the usual manner.

This invention particularly and specifically relates to the unitaryconstruction of the fibrous filter plate members 14. The fibrous filterplate member has encasing or enclosing means 19, 19 of a suitable filtermedia, preferably synthetic fiber felt. This may be a bonded felt, suchbeing felt which is composed of fibers, some of which have binderproperties, and which have been subjected to heat and pressure. Thefibers may be thermoplastic or may have any desired cohesive or adhesiveproperties.

The internal drainage member 20 can be composed of a material havingdrainage channels such as a coarse felt, preferably synthetic fibermechanically interlocked felt. The drainage member is shaped so that ithas a drainage zone or means 21 extending from an edge or appendedthereto. Usually, a transverse aperture 22 is provided therein extendingacross the member and in registration with the outlet passages 30 and26.

Spacer boarder means or frame means 23 can be of a suitable plasticmaterial having an opening or pocket 24 extending therethrough andincluding a drainage zone or transverse through passage 25 formedtherein, said drainage zone being coextensive with and being arranged toreceive drainage means 21 of drainage member 20. The spacer means 23also can be of the same felt as the face plates and there may be aplurality thereof. Outlet passage 26 is arranged so as to cooperate withpassages 25, 22 in frame 23 and drainage member 20; and inlet passage 27in means 19 and frame 23 are aligned.

may'be die cut to shape.

in abutting relationship with the frames of the press.

As an example, the filter media 19, 19 may be made of a bonded felt0.0100.100 in thickness, such a felt having binder fiber therein so thatpart of the fibers become bonded by cohesion or adhesion under heat. Thespacer plate 23 can be made, for example, of material 43 ,to A" inthickness and the drainage member a similar thickness.

The spacer plate can be made of bonded felt or some suitable plastic.The drainage member can be made of a synthetic fiber mechanicallyinterlocked felt. The various materials can be die cut to shape and thenlaminated in a hot compression step on a fiat bed press.

For example, the heat may be in the range of 200 to 700 F. and thepressure 25 to 1000 p.s.i. The finished thickness of such a plate willbe in the range of to /2. The press elements are arranged so that onlythe peripheral zones will be joined and not the drainage area or the.outlet zone of the drainage member.

a The laminating operation will serve to mount the filter media in theassembly, stiffen the filter plate assembly and develop the bearinggasketing surface.

As a result of the thinner plate, a considerably larger number of platesfor filtering will become available in a frame and filter press of agiven length. Also, there will be no danger of a cast iron separatorplate breaking because of unequal pressure on the two sides of theplate. Further, the plates will be non-metallic so that they will have achemical, electrolytic and biological stability.

Also, the plate can be made one-tenth the weight of a conventionalplate.

3 Various types of synthetic fibers or combination thereof can be used.As an example, linear polyamide fibers known as nylon, acrylic fiberssold under the name .Orlon and polyester fibers sold under the nameDacron. Other fibers includes polyethylene and Vinyon, a copolymer ofvinyl chloride and vinyl acetate. One example of a suitable bonded feltis one composed of 1090% Vinyon and 90-10% Dacron. By using non-wovenfelt, the defect of blinding due to apparent collection of particles atthread intersections is eliminated. A further form is illustrated inFIG. 5 wherein an open drainage means A having valve 30B is suitablyfastened to the assembly 31, such being usable as is well known in theart to provide alternate outlets. One of the outlets can have back washwater introduced therethrough when desired. Assembly 31 may be similarto that describe for FIGS. 2 and 3.

Referring to FIG. 6, the filter plate 14 (FIG. 1) may be replaced by afilter plate assembly comprising a central .plate 32 having transversethrough holes 33, 34, 35, 36 and 37. This plate may be made from aplastic or hard pressed bonded fiber that is coated on both sides with apolyethylene or other heat sealing film,'after which it By bonded fiberis meant, besides others, a mixture of plastic fibers having differentmolecular weights and melting points so that heating to a predeterminedtemperature under a predetermined pressure causes the fibers of lowermelting temperature to become tacky, bonding the fibers of highermelting temperature into a semisolid mass. Frame members 38 made from aplastic material may be placed on each side of the central plate 32 andthe assembly may be heat sealed or otherwise integrally joined. Thisprovides pockets 39 and 40 on each side of central plate 32 for thereception of drainage members 41 and 42, which latter may be in the formof a lattice. The lattice drainage members 41 and 42 may be made fromstainless steel or the like, but

preferably are molded from aplastic such as 30% poly- 4 propylene and70% of a lower melting thermoplastic material.

A sheet 43 of filtering media may be heat sealed to the borders of theframes 38 to complete the filter plate assembly. Sheets 43 may be madefrom felted polypropylene bonded fibers, one example of which may be 45%polypropylene fibers and 55% polypropylene binder. The central plate 32may also be made from this mixture.

The through passage 33 may include slots 44 that form drainage passagesleading from the pockets 39 and 40 to the through hole 33. The hole 33is aligned with corresponding holes in elements 38 and 43; however, suchcorresponding holes do not include slots 44. The holes 34, 35, 36 and 37do not communicate with the pockets 39.and 40, but are aligned withcorresponding holes in the elements 38 and 43.

When the filter press plate assembly of FIG. 6 is substituted for fiberplates 14 of FIG. 1, the holes 33 communicate with the outlet line; theholes 34 communicate with the inlet line 18; and the holes 35 may beemployed with a line (not shown) that equalizes the pressure of fiber,spaced transverse passage means arranged in and extending through saidplate member adjacent the periphery thereof, a frame member on each sideof said plate member, generally corresponding in shape with said platemember, each frame member being of plastic bonded fiber and having aninner periphery defining a pocket therein, spaced transverse throughpassage means in said frame members in alignment with said passage meansin said plate member, plastic lattice drainage members removablyarranged in said pockets and being of substantially the same thicknessas said frame members and being coextensive with said pockets, saidlattice members being separated from each other and said central plate,and fiber filter sheets arranged on one side of and attached to saidframe members, said filter sheets having spaced transverse throughpassage means therein in alignment with said through passage means insaid frame members and said central plate member.

2. A filter plate assembly according to claim 1, wherein said' framemembers and said filter sheets are integrally bonded to each other andto said central plate member.

3. A filter plate assembly according to claim 1, wherein said centralplate is of hard pressed bonded fiber coated on both sides with a heatsealing film.

References Cited by the Examiner UNITED STATES PATENTS 393,633 .11/1888Enzinger 2l0228 1,282,414 10/1918 Hagstrom 21023l 1,308,438 7/1919Miller 210-231 1 2,006,131 6/1935 Durant 210- 226 2,122,259 6/1938McKenna 210-23l 2,186,501 1/1940 Seligman et al. 210228 2,594,518 4/1952Teale 210-231 2,788,901 4/1957 Boeddinghaus et a1. 210-486 2,830,3594/1958 Reinshagen 29-l63.5 3,007,238 11/1961 Pail 29-1635 OTHERREFERENCES Dupont Industrial Coated Fabrics 194, Scientific American,No. 3, page 1, March 1956.

REUBEN FRIEDMAN, Primary Examiner. HERBERT L. MARTIN, Examiner.

1. A FILTER PLATE ASSEMBLY FOR A FILTER PRESS COMPRISING IN COMBINATION,A CENTRAL PLATE MEMBER OF PLASTIC BONDED FIBER, SPACED TRANSVERSEPASSAGE MEANS ARRANGED IN AND EXTENDING THROUGH SAID PLATE MEMBERADJACENT THE PERIPHERY THEREOF, A FRAME MEMBER ON EACH SIDE OF SAIDPLATE MEMBER, GENERALLY CORRESPONDING IN SHAPE WITH SAID PLATE MEMBER,EACH FRAME MEMBER BEING OF PLASTIC BONDED FIBER AND HAVING AN INNERPERIPHERY DEFINING A POCKET THEREIN, SPACED TRANSVERSE THROUGH PASSAGEMEANS IN SAID FRAME MEMBERS IN ALIGNMENT WITH SAID PASSAGE MEANS IN SAIDPLATE MEMBER, PLASTIC LATTICE DRAINAGE MEMBERS REMOVALBLY ARRANGED INSAID POCKETS AND BEING OF SUBSTANTIALLY THE SAME THICKNESS AS SAID FRAMEMEMBERS AND BEING COEXTENSIVE WITH SAID POCKETS, SAID LATTICE MEMBERSBEING SEPARATED FROM EACH OTHER AND SAID CENTRAL PLATE, AND FIBER FILTERSHEETS ARRANGED ON ONE SIDE OF AND ATTACHED TO SAID FRAME MEMBERS, SAIDFILTERS SHEETS HAVING SPACED TRANSVERSE THROUGH PASSAGE MEANS THEREIN INALIGNMENT WITH SAID THROUGH PASSAGE MEANS IN SAID FRAME MEMBERS AND SAIDCENTRAL PLATE MEMBER.